Charging member, process cartridge, and electrophotographic image forming apparatus

Abstract

Provided is a charging member exhibiting a stable charging performance even by long-term use. The charging member includes a support and a surface layer on the support, and the surface layer contains a magnesium oxide particle, and a compound having a specified structure.

What is claimed is: 
     
         1 . A charging member comprising:
 a support; and   a surface layer on the support,   wherein the surface layer contains   a magnesium oxide particle; and   a compound represented by a following formula (a) or a compound represented by a following formula (b):   
       
         
           
           
               
               
           
         
       
       (in the formula (a), 
       L1 represents polymetalloxane having a structural unit represented by M1O n/2  wherein when metal atom M1 has a valence of p, n represents an integer of 1 or more and p or less, 
       M1 represents at least one metal atom selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, W, Al, Ga, In, and Ge, 
       X1 represents a structure represented by any one of following formulae (1) to (4), 
       Y1 represents a group having a site coordinated with M1 in L1, and 
       (i) when X1 is a structure represented by the formula (1), A1 represents an atomic group necessary for forming a 4 to 8 member ring together with M1, X1, and Y1, and containing an aromatic ring in which one carbon atom constituting the aromatic ring is bonded to an oxygen atom of X1, and 
       (ii) when X1 is a structure represented by any one of the formulae (2) to (4), 
       A1 represents a bond or atomic group necessary for forming a 4 to 8 member ring together with M1, X1, and Y1: 
       
         
           
           
               
               
           
         
       
       in the formulae (1) to (4), symbol “*” represents a bonding site with A1, and symbol “**” represents a bonding site with M1 in L1, 
       
         
           
           
               
               
           
         
       
       in the formula (b), 
       L2 represents polymetalloxane having a structural unit represented by M2O m/2  wherein M2 represents at least one metal atom selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, W, Al, Ga, In, and Ge, and 
       when metal atom M2 has a valence of q, m represents an integer of 1 or more and q or less, 
       R21 to R25 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a trimethylsilyl group, and 
       a cyclopentadienyl group is coordinated with the metal atom M2 in L2. 
     
     
         2 . The charging member according to  claim 1 , wherein in the formula (a), Y1 is a hydroxyl group, an alkoxy group, a substituted or unsubstituted aryloxy group, a carbonyl group, an alkylthio group, a substituted or unsubstituted arylthio group, a thiocarbonyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted imino group, a group having a substituted or unsubstituted aliphatic heterocyclic skeleton, or a group having a substituted or unsubstituted aromatic heterocyclic skeleton. 
     
     
         3 . The charging member according to  claim 1 , wherein when X1 in the formula (a) is a structure represented by the formula (1), A1 is an atomic group containing an aromatic ring selected from the group consisting of substituted or unsubstituted benzene ring, substituted or unsubstituted naphthalene ring, substituted or unsubstituted pyrrole ring, substituted or unsubstituted thiophene ring, substituted or unsubstituted furan ring, substituted or unsubstituted pyridine ring, substituted or unsubstituted indole ring, substituted or unsubstituted benzothiophene ring, substituted or unsubstituted benzofuran ring, substituted or unsubstituted quinoline ring, and substituted or unsubstituted isoquinoline ring. 
     
     
         4 . The charging member according to  claim 1 , wherein when X1 in the formula (a) is a structure represented by any one of the formulae (2) to (4), A1 is
 a bond,   an alkylene group,   or   an atomic group containing an aromatic ring selected from the group consisting of substituted or unsubstituted benzene ring, substituted or unsubstituted naphthalene ring, substituted or unsubstituted pyrrole ring, substituted or unsubstituted thiophene ring, substituted or unsubstituted furan ring, substituted or unsubstituted pyridine ring, substituted or unsubstituted indole ring, substituted or unsubstituted benzothiophene ring, substituted or unsubstituted benzofuran ring, substituted or unsubstituted quinoline ring, and substituted or unsubstituted isoquinoline ring.   
     
     
         5 . The charging member according to  claim 1 , wherein in the formula (a),
 a ring formed by A1, M1, X1, and Y1 is a 5-member ring or a 6-member ring.   
     
     
         6 . The charging member according to  claim 1 , wherein the polymetalloxane has a structural unit represented by SiO r/2  (r is an integer of 1 or more and 4 or less). 
     
     
         7 . A charging member comprising:
 a support; and   a surface layer on the support,   wherein the surface layer contains   a magnesium oxide particle; and   a polymetalloxane having a structure represented by structural formula (c1) below, and wherein   
       in the polymetalloxane, M3 is bonded to a carbon atom in a structural unit represented by a following structural formula (c2) with a linking group represented by a following structural formula (c3):
   M3O (k−(s+1))/2 (L3) s   Structural formula (c1)
 
 
       
         
           
           
               
               
           
         
       
       in the formula (c1), 
       M3 represents any one of metal atoms of Ti, Zr, Hf, V, Nb, Ta, W, Al, Ga, In, and Ge, s represents an integer of 0 or more and k or less, 
       when M3 is A1, Ga, or In, k=3, 
       when M3 is Ti, Zr, Hf, or Ge, k=4, 
       when M3 is Nb, Ta, or W, k=5, 
       when M3 is V, k=3 or 5, and 
       L3 represents a ligand having a structure represented by a following formula (d) or a ligand having a structure represented by a following formula (e): 
       
         
           
           
               
               
           
         
       
       in the formula (d), 
       X2 represents a structure represented by any one of a following formulae (5) to (8), 
       Y2 represents a group having a site coordinated with M3, 
       A2 represents a bond or atomic group necessary for forming a 4 to 8 member ring together with M3, X2, and Y2, and symbol “**” represents a site bonded or coordinated with M3, 
       
         
           
           
               
               
           
         
       
       in the formulae (5) to (8), symbol “**” represents a bonding site with M3, and symbol “***” represents a bonding site with A2; 
       
         
           
           
               
               
           
         
       
       in the formula (e), R31 to R35 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a trimethylsilyl group, and symbol “****” represents a bonding site with M3; 
       in the formula (c2), R1 to R3 each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and symbol “*1” represents a bonding site with Z in formula (c3), 
       in the formula (c3), 
       Z represents a substituted or unsubstituted phenylene group, and in a substituted phenylene group, a substituent is a halogen atom or an alkyl group having 1 to 3 carbon atoms, symbol “*1” represents a bonding site with the symbol “*1” in the formula (c2), and 
       symbol “*2” represents a bonding site with M3 in the formula (c1). 
     
     
         8 . The charging member according to  claim 7 , wherein A2 is a bond, an alkylene group, or an atomic group containing an aromatic ring selected from the group consisting of substituted or unsubstituted benzene ring, substituted or unsubstituted naphthalene ring, substituted or unsubstituted pyrrole ring, substituted or unsubstituted thiophene ring, substituted or unsubstituted furan ring, substituted or unsubstituted pyridine ring, substituted or unsubstituted indole ring, substituted or unsubstituted benzothiophene ring, substituted or unsubstituted benzofuran ring, substituted or unsubstituted quinoline ring, and substituted or unsubstituted isoquinoline ring. 
     
     
         9 . The charging member according to  claim 7 , wherein Y2 is a hydroxyl group, an alkoxy group, a substituted or unsubstituted aryloxy group, a carbonyl group, an alkylthio group, a substituted or unsubstituted arylthio group, a thiocarbonyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted imino group, a group having a substituted or unsubstituted aliphatic heterocyclic skeleton, or a group having a substituted or unsubstituted aromatic heterocyclic skeleton. 
     
     
         10 . The charging member according to  claim 7 , wherein a ring formed by A2, M3, X2, and Y2 is a 5 member ring or a 6 member ring. 
     
     
         11 . The charging member according to  claim 7 , wherein the polymer having a structural unit containing a phenolic hydroxyl group is a polymer having vinylphenol as a structural unit or a novolac-type phenol resin. 
     
     
         12 . A process cartridge detachable from an electrophotographic image forming apparatus body, the process cartridge comprising:
 an electrophotographic photosensitive member; and   a charging member which charges the surface of the electrophotographic photosensitive member, both members being integrally supported,   wherein the charging member comprises a support, and a surface layer on the support,   the surface layer containing:   a magnesium oxide particle; and   a compound represented by a following formula (a) or a compound represented by a following formula (b):   
       
         
           
           
               
               
           
         
         (in the formula (a), 
         L1 represents polymetalloxane having a structural unit represented by M1O n/2  wherein when metal atom M1 has a valence of p, n represents an integer of 1 or more and p or less, 
         M1 represents at least one metal atom selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, W, Al, Ga, In, and Ge, 
         X1 represents a structure represented by any one of following formulae (1) to (4), 
         Y1 represents a group having a site coordinated with M1 in L1, and 
         (i) when X1 is a structure represented by the formula (1), A1 represents an atomic group necessary for forming a 4 to 8 member ring together with M1, X1, and Y1, and containing an aromatic ring in which one carbon atom constituting the aromatic ring is bonded to an oxygen atom of X1, and 
         (ii) when X1 is a structure represented by any one of the formulae (2) to (4), A1 represents a bond or atomic group necessary for forming a 4 to 8 member ring together with M1, X1, and Y1: 
       
       
         
           
           
               
               
           
         
       
       in the formulae (1) to (4), symbol “*” represents a bonding site with A1, and symbol “**” represents a bonding site with M1 in L1, 
       
         
           
           
               
               
           
         
       
       in the formula (b), 
       L2 represents polymetalloxane having a structural unit represented by M2O m/2  wherein M2 represents at least one metal atom selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, W, Al, Ga, In, and Ge, and
 when metal atom M2 has a valence of q, m represents an integer of 1 or more and q or less, 
 R21 to R25 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a trimethylsilyl group, and 
 a cyclopentadienyl group is coordinated with the metal atom M2 in L2. 
 
     
     
         13 . An electrophotographic image forming apparatus comprising:
 an electrophotographic photosensitive member; and   a charging member which charges the surface of the electrophotographic photosensitive member,   wherein the charging member comprises a support, and a surface layer on the support,   the surface layer containing:   a magnesium oxide particle; and   a compound represented by a following formula (a) or a compound represented by a following formula (b):   
       
         
           
           
               
               
           
         
       
       (in the formula (a),
 L1 represents polymetalloxane having a structural unit represented by M1O n/2  wherein when metal atom M1 has a valence of p, n represents an integer of 1 or more and p or less, 
 M1 represents at least one metal atom selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, W, Al, Ga, In, and Ge, 
 X1 represents a structure represented by any one of following formulae (1) to (4), 
 Y1 represents a group having a site coordinated with M1 in L1, and 
 (i) when X1 is a structure represented by the formula (1), A1 represents an atomic group necessary for forming a 4 to 8 member ring together with M1, X1, and Y1, and containing an aromatic ring in which one carbon atom constituting the aromatic ring is bonded to an oxygen atom of X1, and 
 (ii) when X1 is a structure represented by any one of the formulae (2) to (4), A1 represents a bond or atomic group necessary for forming a 4 to 8 member ring together with M1, X1, and Y1: 
 
       
         
           
           
               
               
           
         
       
       in the formulae (1) to (4), symbol “*” represents a bonding site with A1, and symbol “**” represents a bonding site with M1 in L1, 
       
         
           
           
               
               
           
         
       
       in the formula (b), 
       L2 represents polymetalloxane having a structural unit represented by M2O m/2  wherein M2 represents at least one metal atom selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, W, Al, Ga, In, and Ge, and
 when metal atom M2 has a valence of q, m represents an integer of 1 or more and q or less, 
 R21 to R25 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a trimethylsilyl group, and 
 a cyclopentadienyl group is coordinated with the metal atom M2 in L2.